Clarification on debug output

[mike-oakley]

Hi,

I'm experimenting with the usage-pure mode to polyfill. The debug output from the plugins seems to indicate that no polyfills are applied - every source file has a debug output of:
Based on your code and targets, the corejs3 polyfill did not add any polyfill.
Based on your code and targets, the regenerator polyfill did not add any polyfill.

However, when I look at the output JS, I can see that polyfills (such as Promise) have been applied (as I would expect). How come none of the applied polyfills are mentioned in the debug output? Am I missing them being applied elsewhere or is this a quirk of the new polyfills plugins? Thanks!

For information:
I have a browserslist config in package.json of > 0.25%, not dead, which gives a targets list of:

Using targets: {
  "chrome": "85",
  "edge": "88",
  "firefox": "85",
  "ie": "11",
  "ios": "12.2",
  "opera": "73",
  "safari": "13.1",
  "samsung": "13"
}

My Babel config looks like this:

{
  "presets": [
    [
      "@babel/typescript",
      {
        "jsxPragma": "h"
      }
    ],
    [
      "@babel/preset-env",
      {
        "useBuiltIns": false,
        //"modules": false,
        "bugfixes": true,
        "debug": true
      }
    ]
  ],
  "plugins": [
    "@babel/proposal-class-properties",
    "@babel/proposal-object-rest-spread",
    [
      "@babel/plugin-transform-react-jsx",
      {
        "pragma": "h",
        "pragmaFrag": "Fragment"
      }
    ],
    [
      "babel-plugin-transform-builtin-extend",
      {
        "globals": ["Error"]
      }
    ],
    [
      "@babel/transform-runtime",
      {
        "regenerator": false,
        "debug": true
      }
    ],
    ["polyfill-corejs3", {
      "method": "usage-pure",
      "debug": true
    }],
    ["polyfill-regenerator", {
      "method": "usage-pure",
      "debug": true
    }]
  ]
}

[mike-oakley]

Worth mentioning that switching to using the basic preset-env useBuiltins: "usage" (without the polyfill plugins) outputs the applied polyfills I would expect in it's debug - so maybe the debug output is incorrect in the polyfill plugins?

[nicolo-ribaudo]

I'm surprised that this gives a different output than @babel/preset-env since @babel/preset-env uses this package internally 🤔

I'll investigate.